Once upon a time, in a faraway kingdom called Staten Island, a young man named Robert Diggs steeped himself in two disciplines: the hip-hop culture of the greater New York area and the 1970s martial arts movies of Hong Kong’s Shaw Brothers studio. Out of this fusion came the rap ensemble Wu-Tang Clan in the mid-1990s and — belatedly and not entirely regrettably — a new movie, “The Man With the Iron Fists,” starring, directed by, and co-written by Wu-Tang majordomo RZA.

The film, which wasn’t screened for critics, is lunatic, slipshod, absurdly violent, horribly acted, and borderline incomprehensible. It’s also more goofily entertaining than it has any right to be. This should not be confused with “good,” but it does put “The Man With the Iron Fists” close in grindhouse spirit to the movies that inspired it. If you’ve put your time in with Shaw Brothers classics like “The Kid With the Golden Arm” and “Crippled Avengers” — co-writer Eli Roth and presenter Quentin Tarantino have — you’ll probably feel you got your money’s worth in ham-handed homage.